The types of bioreactors used for shoots and embryos

Plant regenerated organs such as shoots, bulbs, microtubers, corms, embryos, etc. have been successfully proliferated in the bioreactor. The use of a bioreactor leads to the development of technology suitable for large scale plant propagation. The basic construction and characteristics of various types of bioreactor systems are reviewed in relation to shoot and embryo cultures. A pilot scale 500 liter bioreactor system was applied to the production of large scale Stevia rebaudiana shoots.Abbreviations DW dry weight - EC electrical conductivity - FW fresh weight - ORP oxidation-reduction potential     

Synthesis of sulfated derivatives of curdlan and their anti-HIV activity

Sulfopropyl curdlan was synthesized, its structure was determined, and the anti-HIV activity was compared with that of standard curdlan sulfates obtained with piperidine N-sulfonic acid in dimethyl sulfoxide. It was shown that sulfopropyl curdlan exhibits weaker anti-HIV activity than curdlan sulfate. Curdlan sulfates were synthesized with a SO₃-pyridine complex in a heterogeneous phase. It was shown from ¹³C-NMR spectra of acetylated curdlan sulfates that they had a different substituent distribution from standard curdlan sulfate. The cytotoxicity of the curdlan sulfates was attributed to their heterogeneous structure.     

Correction to: Comparison of the usability of an automatic sleep staging program via portable 1-channel electroencephalograph and manual sleep staging with traditional polysomnography

Sleep and Biological Rhythms -     

Variations in and Inheritance of NS-Glycoprotein in Self-Incompatible Brassica campestris L.

The stigma of Brassica species contain NS-glycoproteins thatexhibit a high degree of structural homology to the S-glycoproteinsof self-incompatibility. Inheritance of and variations in theNS-glycoprotein were studied with reference to self-incompatibility.The detection of NS-glycoproteins was performed by cross-reactionwith an antiserum raised against a purified NS-glycoprotein.In B. campestris, four isoforms of the NS-glycoprotein weredifferentiated by their pI values, but their molecular weightswere identical to one another. The genes for these isoformsof NS-glycoprotein were controlled by alleles at a single locus,tentatively named the NS allele, which was independent of Salleles at both the protein and the DNA level. Segregation ofF₂ plants with respect to the self-incompatibility behaviorof pollen tubes can be explained by the S allele model, butit appears not to be affected by the NS alleles. NS-glycoproteinswere found in all 21 species of Brassica and its allies examinedto date. The pI values of these glycoproteins varied among differentspecies. In addition to the isoforms of the NS alleles, maturestigmas contained other groups of proteins that reacted weaklywith the antiserum against the NS-glycoprotein. (Received July 30, 1991; Accepted February 21, 1992)     

Accumulation of glutamate by osmotically stressed Escherichia coli is dependent on pH.

In the present study, we measured the accumulation of glutamate after hyperosmotic shock in Escherichia coli growing in synthetic medium. The accumulation was high in the medium containing sucrose at a pH above 8 and decreased with decreases in the medium pH. The same results were obtained when the hyperosmotic shock was carried out with sodium chloride. The internal level of potassium ions in cells growing at a high pH was higher than that in cells growing in a neutral medium. A mutant deficient in transport systems for potassium ions accumulated glutamate upon hyperosmotic stress at a high pH without a significant increase in the internal level of potassium ions. When the medium osmolarity was moderate at a pH below 8, E. coli accumulated gamma-aminobutyrate and the accumulation of glutamate was low. These data suggest that E. coli uses different osmolytes for hyperosmotic adaptation at different environmental pHs.     

Expression of Biologically Active Basic Fibroblast Growth Factor by Genetically Modified Rat Primary Skin Fibroblasts

Abstract: Basic fibroblast growth factor (FGF-2) is normally expressed as a cell-associated protein, and accordingly it is not clear how it exerts its action on target cells in vivo. It has been proposed that cells release, by death or other mechanisms, small amounts of FGF-2 that then acts in an autocrine manner. To address the question of whether it is necessary that FGF-2 remain cell associated or needs to be secreted from cells to have biological activity, we expressed the 18-kDa form of FGF-2 in primary fibroblasts as a cell-associated (FGF-2-B) or as a secreted (FGF-2-S) protein. FGF-2 protein is detected in cell lysates and membrane fractions of both cell types, whereas it is present in significant amounts only in the conditioned medium of FGF-2-S cells. No FGF-2 is detected in control (untransfected) cells. FGF-2-S cells also grow faster than the control or FGF-2-B cells. Yet, when evaluated for their ability to promote the survival of embryonic hippocampal neurons in vitro, both the cell types are active, establishing the activity of the transgene product. We conclude that FGF-2 is active when engineered to be expressed as a cell-associated form or secreted from cells.     

Establishing apoptosis resistant cell lines for improving protein productivity of cell culture

The authors established apoptosis resistant COS–1, myeloma, hybridoma, and Friend leukemia cell lines by genetically engineering cells, aiming at more efficient protein production by cell culture. COS–1 cells, which are most widely used for eukariotic gene expression, were transfected with human bcl–2 gene. Both bcl–2 and mock transfected COS–1 cells were cultured at low (0.2%) serum concentration for 9 days. The final viable cell number of the bcl–2 transfected cells was ninefold of that of the mock transfectants. Both bcl–2 and mock transfectants were further transfected with the vector pcDNA- containing SV40 ori and immunoglobulin gene for transiently expressing protein. The bcl–2 expressing COS–1 cells produced more protein than the mock transfected COS–1 cells after 4 days posttransfection.Mouse myeloma p3-X63-Ag.8.653 cells, which are widely used as the partner for preparing hybridoma, and hybridoma 2E3 cells were transfected with human bcl–2 gene. Both bcl–2 transfected myeloma and hybridoma survived longer than the corresponding original cells in batch culture. The bcl–2 transfected 2E3 cells survived 2 to 4 four days longer in culture, producing 1.5- to 4-fold amount of antibody in comparison with the mock transfectants.Coexpression of bag–1 with bcl–2 improved survival of hybridoma 2E3 cells more than bcl–2 expression alone. The bag–1 and bcl–2 coexpressing cells produced more IgG than the the cells expressing bcl–2 alone.Apoptosis of Friend murine erythroleukemia(F-MEL) cells was suppressed with antisense c-jun expression. The antisense c-jun expressing cells survived 16 days at non-growth state.     

Cooperative Interception of Neuronal Apoptosis by BCL-2 and BAG-1 Expression: Prevention of Caspase Activation and Reduced Production of Reactive Oxygen Species

Abstract: Neuronally differentiated PC12 cells undergo synchronous apoptosis when deprived of nerve growth factor (NGF). Here we show that NGF withdrawal induces actinomycin D- and cycloheximide-sensitive caspase (ICE-like) activity. The peptide inhibitor of caspase activity, N -acetyl-Asp-Glu-Val-Asp-aldehyde, was more potent than acetyl-Tyr-Val-Ala-Asp-chloromethyl ketone in preventing NGF withdrawal-induced apoptosis, suggesting an important role for caspase-3 (CPP32)-like proteases. We observed a peak of reactive oxygen species (ROS) 6 h after NGF withdrawal. ROS appear to be required for apoptosis, because cell death is prevented by the free radical spin trap, N-tert -butyl-α-phenylnitrone, and the antioxidant, N -acetylcysteine. ROS production was blocked by actinomycin D, cycloheximide, and caspase protease inhibitors, suggesting that ROS generation is downstream of new mRNA and protein synthesis and activation of caspases. Forced expression of either BCL-2 or the BCL-2-binding protein BAG-1 blocked NGF withdrawal-induced apoptosis, activation of caspases, and ROS generation, showing that they function upstream of caspases. Coexpression of BCL-2 and BAG-1 was more protective than expression of either protein alone.